1. Field of the Invention
The present invention relates to a motorized equipment having a controller provided on one axial side of a shaft of an electric motor.
2. Description of Related Art
Conventionally, electric power steering for assisting steering, which is performed by a driver, has been publicly known. Reduction of a size and weight and enhancement of an output of a motor used for the electric power steering are required.
A motor described in Patent document 1 (JP-A-2003-204654) has a controller, which drives and controls an electric motor, provided parallel to an axial direction of a shaft of the electric motor. The electric motor is composed of a motor case, a stator, a rotor, the shaft and the like (refer to FIGS. 14 and 15 of Patent document 1). The controller is composed of a heat sink, a metallic substrate, a control board and the like. The heat sink is fixed to a radially outer wall of the motor case of the electric motor. The metallic substrate mounted with a power transistor is fixed to the heat sink. The control board is attached to an opposite side of the heat sink at a predetermined distance from the metallic substrate.
As for connection of wirings of the electric motor and the controller, lead wires electrically connected with a coil, which is wound around the stator, extend in a direction perpendicular to the axis of the shaft and are connected with wirings of the metallic substrate. Lead wires extending from a position sensor, which can sense a rotation angle of the rotor, extend in a direction perpendicular to the axis of the shaft and are connected with wirings of the control board.
A motor described in Patent document 2 (JP-A-2002-345211) has a controller provided on an axial end side of a shaft of an electric motor (refer to FIGS. 1 to 3 of Patent document 2). A heat sink constituting the controller is attached to block an opening of a cylindrical motor case of the electric motor. A metallic substrate mounted with a power transistor is attached to the heat sink. A control board is attached to an opposite side of the heat sink at a predetermined distance from the metallic substrate.
As for connection between wirings of the electric motor and the controller, winding terminals extending from a coil, which is wound around a stator, extend parallel to an axis of a shaft and are connected with electric motor terminals extending from the metallic substrate. Sensor terminals connected to a position sensor, which can sense a rotation angle of the rotor, extend through a magnetic sensor holding section, which is made of a resin, and are connected with wirings of the control board.
An output of the electric motor of the motor used for the electric power steering is set differently according to weight and the like of a type of vehicle, to which the motor is applied. If an amount of heat generation of the power transistor changes according to the setting of the output of the electric motor, a necessary heat capacity of the heat sink changes. Therefore, a volume of the heat sink is changed.
If the setting of the output of the electric motor changes in the construction of the motor described in Patent document 1, a distance between a radially outer wall of the motor case and the metallic substrate and a distance between the radially outer wall of the motor case and the control board change with the change in the volume of the heat sink. Therefore, designs of the lead wires electrically connected with the coil, the lead wires extending from the position sensor and the like are changed.
If the setting of the output of the electric motor changes in the construction of the motor described in Patent document 2, a distance between the opening of the motor case and the metallic substrate and a distance between the opening of the motor case and the control board change with the change in the volume of the heat sink. Therefore, designs of the winding terminals extending from the coil, the electric motor terminals extending from the metallic substrate, the sensor terminals connected to the position sensor, the magnetic sensor holding section and the like are changed. In this way, if the designs of the members constituting the controller and the like are changed according to the setting of the output of the electric motor, there is a concern that a manufacturing cost of the motor increases.
Since the motor described in Patent document 1 has the controller arranged parallel to the axial direction of the shaft of the electric motor, there is a concern that a body size in a radial direction increases.
The motor described in Patent document 2 requires a space for performing a connecting process of the electric motor terminals, which extend from the metallic substrate, and the winding terminals, which extend from the coil, between the metallic substrate and the control board. In addition, the motor requires a space for performing a connecting process of the sensor terminals of the position sensor and the control board between the metallic substrate and the control board. Therefore, there is a concern that an axial body size increases.